A single-row cylindrical roller bearing used in a machine tool spindle is often used at high speed rotation (for example, dmN (=(inner diameter of bearing+outer diameter of bearing)/2×rotational speed (rpm)) is 350,000 to 700,000 or more) and under negative radial gap conditions. Under such severe use conditions, since a cage is subjected to a force due to mutual sliding with a roller, an outer ring guide type cage may be used.
However, when the outer ring guide type cage is used, if the lubrication of a guide surface is insufficient, wear occurs in a contact portion between the cage and a outer ring, and there is a possibility that the bearing is damaged. Further, when assembly is performed in a positive radial gap due to variations in installation conditions, the roller may be easily skewed or tilted, and the generation of squeak noise and wear between an inner ring flange surface and a roller end surface due to revolution slip and the like may occur.
Therefore, various roller guide type cages in which wear does not occur between the cage and the bearing ring are known (for example, see Patent Literatures 1 to 3).
For example, in the cylindrical roller bearing described in Patent Literature 1, an outer diameter restraint type cage is disposed. The cage is made of a synthetic resin and prevents forced drawing upon release of a product from a mold for injection molding during resin cage molding and prevents the roller from biting into column portions of the cage. Since a guide gap expands due to centrifugal expansion and thermal expansion during operation, the outer diameter restraint type cage is suitable for a certain high-speed use condition without excessive contact with the roller. When the assembly is performed in the positive radial gap, the roller during operation is pressed to an outer ring side by centrifugal force, an act from an pocket opening portion (roller guide portion) to an inner ring side is pressed by the outer diameter restraint type cage, irregular movement (in particular, skew movement) of rolling elements caused by the positive radial gap is restricted, and it is effective in suppressing the squeak noise and suppressing the wear between the inner ring flange surface and the end surface.